1,720,967 research outputs found
End effects for anti-plane shear deformations of periodically laminated strips with imperfect bonding
No full textThe axial decay of Saint-Venant end effects is investigated for anti-plane shear deformations of semi-infinite generally laminated anisotropic strips. Imperfect bonding conditions are imposed at the interfaces. The analytical approach, using a displacement field which decays exponentially in the axial direction, gives rise to a transcendental equation for the real eigenvalues. The decay rate for the stresses is given in terms of the smallest positive eigenvalue. Laminated strips with periodic layout ale then considered. In the presence of imperfect bonding, the effective shear elastic moduli, computed through a homogenization method, depend on the total number of slipping interfaces in the laminate. Numerical examples confirm that the decay lengths computed with effective shear moduli represent the asymptotic values (for an increasing number of layers) for those of periodically laminated strips
“A Two Point Boundary Value Problem for the Axial Shear of Isotropic Incompressible Nonlinearly Elastic Materials”
No full textThe purpose of this research is to investigate a pure axial shear problem for the annular region between two concentric rigid cylinders occupied by an incompressible isotropic nonlinearly elastic material. Our main concern is with the subclass of these materials that exhibits hardening at large deformations. Such hardening at large strains is observed experimentally but is often not predicted by commonly used strain-energy densities. The particular axial shear problem that we investigate arises when the elastic material is perfectly bonded to an inner rigid circular core and to an outer rigid circular container. The deformation is driven by an axial pressure gradient. The problem is formulated as a two-point boundary-value problem for a second-order nonlinear ODE. For a broad class of incompressible isotropic hyperelastic materials, existence of smooth solutions is established on conversion to an initial value problem. We then specialize the material class to be of generalized neo-Hookean type, that is, where the strain-energy density depends only on the first invariant of the strain tensor. Two classes of such materials that exhibit hardening at large deformations are considered. The first class models limiting chain extensibility at the molecular level, and the second class is of power-law type. An interesting limiting case of the latter leads to an exponential strain-energy function commonly used in modeling biological materials. Some specific strain-energy densities from each class are examined in detail. Numerical boundary-value methods with quasilinearization for nonlinear second-order ODEs are used to illustrate a special feature of the solutions. It was previously shown by other authors that, for softening power-law materials, a boundary layer behavior is exhibited near the bonded surfaces: the axial displacement undergoes a sharp increase from zero at the endpoints and is slowly varying in the interior. We provide further numerical results regarding this phenomenon here. Our main concern is, however, with hardening materials. For such materials, the numerical results exhibit an interior localization at a location which is almost the midpoint between the boundaries. The axial displacement has a sharp change of slope which, in the limit of infinitely large pressure gradients, gives rise to a cusp in the displacement profile. The results highlight the contrasting behavior between softening and hardening rubber-like or biological materials
End effects in multilayered orthotropic strips with imperfect bonding
No full textThe axial decay of Saint-Venant end effects is investigated for plane strain deformations of semi-infinite generally laminated orthotropic strips, subject to self-equilibrated end loading. General imperfect bonding conditions are imposed at the interfaces. The analytical approach, using an Airy stress function which decays exponentially in the axial direction, gives rise to a transcendental equation for the (generally complex) eigenvalues. The decay rate for the stresses is given in terms of the eigenvalue of smallest positive real part. The decay rates are examined analytically and numerically in a number of special cases. These include a bimaterial orthotropic strip and the special subcases of a symmetric single lap joint made of the same material, symmetric orthotropic sandwich strips and the classical symmetric double lap joint. Asymptotic estimates for the decay rates, in the case of large slip, are obtained which predict extremely slow decay of end effects
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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